There are a few ways to do this. The easiest way is to make 2 arrays, one of the original values, and one of the post values, use array_merge() to mash them together. Then have your update statement just update EVERY field. The ones that didn't change will still be updated with their current value, but that won't hurt anything, and the ones that change will get the new values (as long as you put the arrays in the proper order in your array_merge())